Apparatus for controlling electric motors.



No. 654,410. v Patented I kuly 241 |900. F. A. MEHRlCK @L E. w. STULL.APPARATUS FR C-NTHLLING ELECTRIC MOTORS.

(Application med Nov. 22, 1899.)

BWK Arronflfr.

we Nonms Pneus cv., PnoTuLITNO.. wAsmNuvoN, 0.1:.

Nu. 654,4I0.

(No Model.)

Patentd July 24, |900. F. A. MEHRICK & E. W. STULL.

APPARATUS FUR GUNTROLLING ELECTRIC MOTORS.

(Appxicmon mea Nov. 22, 1599.)

3 Sheets-Sheet 2,

*MMA Tram/H.

No. 654,4m, y .Patented my 24, |900.

F. A. MEnmcKe. E. w. -sTuLL. APPARATUS FOR CUNTBOLLING'ELEGTRIC MUTURS.

(Application led Nov. 22, 1899.)

TN: "ohms Ferns w, PHoTo-Llwo.. wAsHwuTow, nc.

NITE STATES PATENT ence.

FRANK -AIMERRICK'AN'D r`EMimErr w. STULL, or JoriNsTowN; rENNsYLvA-YNIA, AssIcNons To THE LonArN STEEL coMPANv, or PENNSYLVANIA.

APPAnx-irosl FoacoNTRoLL-ING.ELECTRIC MOTORS.

srEcrnrcATroN'ferrnng part of Letters Patent No. 654,410, dated Jury 24,leoo.

' `Application liled November 22, 1899. Serial NO- 737|8'79 (N0 modld Beit known that we, FRANK A. MERRIC'K and EMMETT W. STULL, of Johnstown,in the county of Cam bria and State of Pennsylvania,

have invented a new and useful Improvement in Apparatus for the Controlof Electric Motors, of which the following isa full, clear, and exactdescription, reference being had to the accompanying drawings, whichforni a ro part of this specification. U

Our invention has relation to apparatus for the control of electricmotors, and is more particularly designed for use on electric-railwaycars which are propelled by four motors,

although in part it is equally applicable in connection with two motors.

One object of our invention is to provide apparatus by which a pluralityof electric motors may be started from a position of rest in zo whichall their'elements are connected in series and changed over to amultiple position in whichv pairs of the motors are connected inmultiple and the multiple pairs in series with each other through aseries of intermediate circuit changes of suitable character toaccelerate the motors without injury to their coils or brushes. Byha'ndlingthe motors in this manner we are -able to get a maximum effectof torque, particularlyin starting from 3o a position of rest. We alsomake it possible to use a higher potential on the line with less drop inpotential along the line.

A further object of our invention is to provide a brake-controllingswitch of novel char' acter for connecting the motors in a closedcircuit independent oi' theline and in a manner whereby their brakingaction when running as generators driven by the momentum of the car maybe effectively utilized; also,

4o to provide means whereby said switch cannot be operated until themotors have been disconnected from the line-circuit, thereby preventinginjury to the motors by reason of any movement of the brakefswitchtending to cause them to act as generators while they are stillreceiving'current from the line; also,

to provide means whereby the motors cannot be connected with the lineexcept when the brake-switch is at the olf position, so that 5o as longas the motors are connected to run as generators no current can be madeto pass to them from the line. v y

Other minor objects of the invention will hereinafter appear. y

With these objects in View the invention consists iirst in thecombination, with four electric motors, of a pair of controller-drumsintergeared one with the other, so that they may be simultaneouslyoperated by the movem ent of a simple handle-lever, each drum hav- 6oing contacts and connections for changing from series to parallel onepair of the motors through a series of intermediate steps in which thestrength of the fields and the ohmic re,- sistanceof the circuits aregradually changed to gradually accelerate the motors, the two drumsbeing electrically connected in series.

Our invention further consists in a brakecontrolling switch havingcontacts, brushes, and proper electrical connections whereby 7o themotors may be connected to operate as generators and the ohmicresistance of the motor-generator circuit may be reduced as the speed ofthe armatures decreases; also, in the provision of contacts carried bythe brakecontrolling switch and controlling the passage of current fromline to the motors; also, in the provision of an electromagnetic lockingdevice for the brake-switch, whereby it cannot be operated until thecurrent is cut 8o off from the motors.

In connection with the apparatus we employ artificial resistance for therheostatic control of the motors in starting from a position of rest andfor using in the braking-circuit. Ve also employ a combined reversingand cut-out switch having certain novel features hereinafter pointedout.

Referring to the accompanying drawings, Figure 1 is a diagram whichshows the va- 9o rious apparatus and connections for a'fourmotorequipment. Fig. 2 is' a detail view showing the mechanical connectionbetween the two controller-drums. Fig. 3 is a detail View showing thelock for the brake-controller. Fig. 4 is a horizontal section throughthe brake-controller. Fig. 5 is a diagram showing conventionally theseveral positions of the motors for the respective indicated or notchpositions of thecontroller-drums. Fig. roo

6 is a similar View showing the several positions or circuit positionseffected by the operation of the brake-controlling switch.

In the diagrams Figs. 1, 4, and 5, A A2 A3 A'l designate the respectivearmatures of four electric motors, (designated as 1, 2, 3, and 4,) and FF2 Fi Fl the respective fieldcoils of the same.

C C2 designate two controller-dru ms shown in developmentand each ofwhich is provided with a plurality of contacts c/ or c2, arranged uponrotation of the drum to be engaged by contact brushes orV fingers b b2,dce. Drum C/ controls motors 1 and 3, while the drum C2 controls themotors 2 and 4. These drums are mechanically of the well-known cylindertype and need not be further described. The arrangement of cont-acts oneach drum is in accordance with the system and apparatus for controllingmotors described and claimedA in the applications of F. A. Merrick,Serial Nos. 713,690 and 726,928, filed April 4, 1899, and August 11,1899, respectively*that is to say, each drum has contacts so arranged asto change two motors from series to parallel relation through a seriesof intermediate relations in which artificial resistance in series withthe motors is first gradually removed from circuit as their counterelectromotive force increases, then the fields are connected in multiplewith the armatures in series, then the armatures are connected inmultiple and the iields in series, and iinally the two motors as a wholeare connected in multiple. The two drums are duplicates of each other,except that the upper group on the drum C2 are grounded on shaft,whilethe drum C' is provided with a continuous contact o d for the upperbrush b', to which is connected the conductor C D, which connects thetwo drums electrically in series.

g g/ g2 are intermeshing gear-wheels which connect the shaft of the twodrums, and D is the operating handle or lever.

R S represent the reversing and cut-out switch, which is also in generalof a wellknown type, with a plurality of contacts S and brushes b s forengagement therewith. This switch has seven different positions,indicated by the dotted vertical lines and marked, respectively, 2 t 4back, 2 da 4 ahead, A ahead, off, baclg 1 and 3 back,77 H1 and 3 ahead.

The conductor C D is connected to the brush 1227 of the controller C2,and this brush is connected to a contact s4, which is grounded on theshaft of the reversing and cut-out switch. This connection provides animmediate ground connection for motors 1 and 3 when the reversing andcut-out switch is set in position to run these two motors either forwardor backward.

RB', HB2, RBS, and RB*l designate, respectively, four resistance-boxesor rheostats arranged in two pairs, whose individuals are electricallyconnected in each pair and having their elements or resistance unitsarranged and connected so that portions of the resistance of each boxmay be successively cut into and out of circuit by the action of thecontroller-drums C C2 and also by the action of the brake -controllingswitch presently described, each of said drums controlling the relationto circuit of one pair of the boxes.

We do not deem it necessary to describe in detail the grouping andarrangement of t-he various contacts or to specifically point out thevarious electrical connections, as they are best seen and understood byreference to the drawings, and our invention is not limited thereto. Norwill it be necessary to trace out the path of the circuit in the severaldifferent positions of the drums C' C2, as this is graphically shown inFig. 5. By the lettering on the drawings indicating the connections ofthe various leads and conductors this maybe readily done. Referring toFig. it will be seen thatin the first position ofthe said drums all theelements of all four motors are connected in series, the artificialresistance being also in series with the motors, the current passingthrough the armatures and field-coils of motors Nos. 1 and 3, thencethrough one pair of the resistance-boxes RB HB2, and thence through theother two motors and the other pair of resistance-boxes to ground. Atposition No. 2 a part of the resistance is removed from circuit, and atposition No. 3 still more is removed. At position No. 4 the entireresistance is removed, the motors still remaining all in series. Atposition No. 5 the fieldcoils of each pair of motors are connected inmultiple. The circuit is then momentarily opened and the armatures ofeach pair of motors are connected in multiple with the fields in series.This is shown at position No. G. In position No. 7, which is the finalposition, each pair of motors are connected in full multiple. In passingfrom position 4 to position 5 the field-coils of one motor of each pairare temporarily removed from circuit, and in passing from position 6 toposition 7 the circuit is momentarily broken through the armature of onemotor of each pair, and then through the field-coils of the same,preparatory to passing to full multiple connection of each pair. These,however, are not indicated or notch positions of the controller and arenot shown in the diagram Fig. 5. Throughout all these circuit changesthe two pairs of motors remain connected in series. It will be readilyseen that in this way we are able to get the maximum effect of torque instarting the motors, which is important where the load is heavy. Thismethod of control also enables a higher potential to be used on the linewith a much less sudden drop in potential.

We will now proceed to describe our iniproved brake-controlling switch,(shown at BCS in Fig. 1.) This switch consists of a rotary drum similarmechanically to the oontroller-drums and carrying upon its periphery aplurality of contacts which we have marked IOO Z Z' and z c, duc., toZ22. These contacts are arranged in seven electricallydisconnectedgroups. Contacts Z Z constitute one group, contacts z c" z2 z3 e4 z5 thesecond group, contacts ZG and ,e7 the third group, contacts z2 zg @'10 ethe fourth group, contacts cl2 to e, inclusive, the fifth group,contacts als and cl2 the sixth group, and contacts z2() to .222,inclusive, the seventh group. It will be noted that in the arrangementof contacts groups 2 and 5, 3 and 6, and 4 and 7 are respectivelyduplicates. It Will also be noted that if a vertical central line bedrawn through the said groups a similar arrangement of contacts isfound, with the exception of the first group upon each side of said linewith an open space between them. For engagement with these contacts twoopposite sets of brushes or tingers are provided, those at one sidebeing marked P p p p2, &c., to p44, and those at the opposite side R rr' r2, the., to rs. These two sets of brushes are designed to engage,respectively, the duplicated contacts at the two sides of the drum,there being, however, two less brushes of the r group than of the pgroup. The drum has fourpositions in which the brushes 1^ to r and p top9 engage the contacts of the second, third, fourth, fifth, sixth, andseventh groups, and another or off position in which the brushes P and Rengage the contacts Z Z,the other brushes being out of contact. Boeindicates a blowout coil for the said drum, and L C a lockinagnet-coilhaving an armature K, (see Fig. 3,) carrying a pawl K5, arranged toengage a tooth K2 on the shaft of the brake-controller drum. K2 is aspring for retracting the said armature when it is released by themagnet. Thebrush R is connected to the trolley or high-potential side ofthe line through the usual car Wiring and instruments, as shown, and thebrush P is connected to the lbottom brush of the controller-drum Cthrough the magnet-coil L C, as shown. The circuit from the trolley tothe controllers C' C2 and the motors must therefore pass through thebrush R, contacts Z Z', and coil L C. Therefore no current can pass tothe motors except the brake-controller is in its off position, and solong as the current is passing to the motors the coil L C is energizedand keeps the armature-pawl K' in engagement withl the tooth K2. Thebrake-controller is thereby locked and cannot be operated until thecurrent is cut off from the motors. Brush p is connected to the negativeside of the armature A4 and brush p11 to the positive side of the same.Brushes p, p2, and p2 are connected to tWo of the resistance-boxes.Brush p2 is connected to the negativev side of the fieldcoil F and brushp4 to the positive side of the same. Brush p5 is connected to thepositive side of armature A3 and brush p6 to the negative side of thesame. Brush p7 is connected to ground. Brush p9 is connected to thenegative side of the field-coils F2 and brush p40 to the positive sideof the same.

Brush r is connected to the negative side of armature A2 and brush r2 tothe ositive side of the same. Brushes r r6 are connected to theresistance, brush r2 to the negative side of field-coils F2, and brushr2 to the positive side of the same, brush r4 to the positive side ofarmature A', and brush T5 to the negative side of the same. Brush T7 isconnected to the negative side of field-coils F4, and brush r2 to thepositive side of the same through the blow-out coil B00. The variousconnections are made by means of branches to the main leads. When thedrum is moved to the iirst position indicated by the dotted verticallines l, the circuit from line to the motors is broken and the path ofthe current may be traced as follows: from the positive brushes of thearmatures A2 and A4 in multiple to the brushes r9 p41, contacts 522.222, brush p40, field-coils F2 to brush 9, contacts 518549, brush frs,field-coils F4, resistance-boxes R132 HB4 to brush p7, contacts @44 .242542. The path of the current is here divided, the contact ,212 beingconnected to the negative brush of the armature A through brush 15,while the contact Z13 is connected to the negative brush of the armatureA3 through the brush p6. The current from the positive brushes of thesaid armatures meets in the contacts of the fourth group through thebrushes r4 p5 and, uniting, passes to field F by brush p4, returning tocontact z, thence by contact .c7 and brush r2 to the field-coil F2,thence through resistance RB R132, thence to brush fr', thence tocontacts z z', and to the negative brushes of the respective armaturesA2 A4.

It will be seen that the motors are connected in circuit relationsimilar to positions 6 of t-he controllers C C2, eXceptthat theresistance is in circuit and the armature connections are reversed. Inposition 2 brush p7 loses its connection With contact 218 and insteadbrush r6 engages the contact 215. Brush p also loses engagement withcontact a2 and brush r' engages contact z2. The effect of these changes,it will be readily seen, is to out out portions, respectively, of theresistances RB BB3 by shortcircuiting them. In position No. 3 thebrushes r6 and r' become disengaged from the respective contacts c45 ande2 and instead brushes p8 and p2 engage, respectively, the contacts zwand a4. This shortcircuits still more of the resistance. In position No.4 brushes p8 and 192 lose their respective engagements and brushes r2and ri' engage, respectively, the contacts z5 and 547. This, it will beseen, short-circuits the entire resistance by providing a direct returnpath to the brake-controller from the negative sides of fields F and F4.The connection of the motors remains unchanged in positions 2, 3, and 4.

By placing the armatures in multiple and the fields in series while themotors are running as generators We are enabled to keep up the strengthof the fields as the speed of the armatures decreases, so that combinedwith IOO IIO

4 static the decrease in the ohmic resistance of the motor-generatorcircuit by gradually removing the artificial resistance anearly-constant and properly-regulated braking action results, thepotential of the current generated being nearly the same as that atwhich the motors run when connected with the line-circuit.

By the described arrangement of the contacts with duplicate brushes weprovide a Very compact construction of switch. The contacts of thefourth and seventh groups effeet the multiple connection of thearmatures and their connection with the fields, the contaets of thethird and sixth groups effect the ser-ies connection of the fields, andthe contacts of the second and seventh `groups control the resistance.

This switch, it will be seen, may be readily adapted for use inconnection with a single pair of motors by omitting one group of each ofthe duplicate groups and is applicable also for use in connection withvarious types and constructions of the motor-controllers.

It is obvious that the particular construction and arrangement which wehave herein shown and described may be varied without departing from ourinvention as ,hereinafter claimed. Hence we do not wish to be limited tononessential and unimportant details.

Having thus described our invention, what we claim, and desire to secureby Letters Patent, is

l. The combination with four electric m0- tors, of two controller-drums,each of which has contacts and connections for changing one pair of saidmotors from series to parallel, said drums being electrically connectedin series with each other.

2. The combination with four electric motors, of two controller-drums,each of which has contacts and connections for changing one pair of saidmotors from series to parallel, said drums being electrically connectedin series with each other, and gear connections' between the shafts ofsaid drums whereby they may be operated in unison.

3. The combination with four electric motors, of two controller-drumselectrically connected in series, one with the other, and mechanicallyintergeared to rotate in unison, each of said drums having contacts andeennections for connecting two motors in series, with either element ofone motor in series with the corresponding element of the other motor,and the other elements in multiple, or with the two motors as a whole inparallel.

4. The combination with four electric motors, of two controller-drumsmechanically connected to rotate in unison, and each having contacts',whereby two of the motors may be connected in series, or with theirarmatures in series and their fields in parallel, or with their fieldsin series and their armatures in parallel, or in parallel as a whole,and means for maintaining a series connection between the said drums inall positions thereof.

5. The combination with a plurality of elecAl tric motors, and acontroller therefor, of a brake controlling switch having contacts whichcontrol the connection of the motors and the said controller to line andwhich break such connection when the brale-controlling switch is movedfrom its ol'f position.

6. The combination with a plurality of electric motors, ofabrake-controlling switch, and an electro magnetic locking device forsaid switch in circuit with the motors, whereby said switch can beactuated only when the motors are disconnected from line.

7. The combination with a plurality of electric motors, of abrakecontrolling switch therefor, a magnet-coil in circuit with themotors, an armature having a pawl for locking engagement with the shaftof said switch, whereby the latter is released only when the circuitthrough the motors is broken.

8. The combination with a plurality of electric motors,of abrake-controlling switch connected with the motor-circuit, contacts onsaid switch which control the connection of the motors with theline-circuit and which break such connection when the switch is movedfrom its off positions, a magnet-coil also in the motor-circuit, and anarmaturepawl controlled by said coil engaging the shaft of said switch,whereby the latter is released only when the circuit through the motorsis broken.

0. The combination with four electric motors, and a pair ofcontroller-drums for connecting said motors and their elements indifferent circuit relations, of a combined revers ing and cut-out switchalsol in circuit with said motors, said switch having a grounded contactand means for establishing a direct connection between said contact andtwo of the motors in certain positions of said switch.

10. The combination with a plurality of electricmotors, of an electricbrake-controlling switch having contacts and connections whereby themotors may be placed in a closed circuit independently of line, withtheir armatures in multiple and their fields in series, and theirarmature connections reversed.

1l. The combination with four electric motors, and artificial resistancefor connection in circuit therewith, of a switch for connecting saidmotors in a closed circuit to run as generators, and having contacts andconnections whereby the motors may be series connected in two pairs withthe armatures of each pair in multiple and their fields in series, andother contacts for connect-ing in circuit more or less of the saidresistance.

12. The combination with a plurality of electric motors,controlling-switch therefor, consisting of a rotating drum havingtherein duplicate sets of contaets,a set of brushes or fingers for eachset of contacts, and the necessary electrical connections whereby assaid drum is rotated, the motors are connected in a local circuit, torun as generators, part of IOO the said circuit being effected throughone set of contacts and ingers and another part through the other set ofcontacts and ngers.

13. A brake-controlling switch for four motors having fixed contactfingers or brushes, and a rotary drum having two duplicate groups ofcontacts, each of which groups is arranged to connect the field-coils ofone pair of motors in series,two other duplicate groups, each of whichis arranged to connect the armatures of one pair of said motors inmultiple to run as generators, and two other duplicate groups to insertin and remove from the circuit an artificial resistance.

14. A brake-controlling switch for four motors having fixed contactfingers or brushes, and a rotary drum having two duplicate groups ofcontacts, each of which groups is arranged to connect the field-coils ofone pair of motors in series,two other duplicate groups, each of whichis arranged to connect the armatures of one pair of said motors inmultiple to run as generators, and two other duplicate groups to insertin and remove from the circuit au artificial resistance, said groupsbeing also divided into two duplicate sets, and the said brushes beingarranged in two different sets, one set for each set of contacts.

l5. A brake-controlling switch for four moik tors having liXed contactfingers or brushes,

and a rotary drum having two duplicate groups of contacts, each of whichgroups is arranged to connect the eld-coils ot' one pair of motors inseries, two other duplicate groups each of which is arranged to connectthe armatures of one pair of said motors in multiple to run asgenerators, and two other duplicate groups to insert in and remove fromthe circuit an artificial resistance, and other contacts for connectingthe motors in circuit with the line when the switch is in oftl position.

In testimony whereof we have axed our signatures in presence of twowitnesses.

FRANK A. MERRICKI, EMMETT W. S'IULLA Witnesses:

MYRTLE E. SHARPE, ANNIE M. Mosns.

